I consolidated most of my setup to Leica M, but I still keep my Canon 1V and a handful of lenses. As fotch said, it's useful to keep an SLR around. So I have a 28, a 50, and a 200 for my SLR. I wouldn't get that much money for the first two, and the 200 is something I can't duplicate with a rangefinder. Couple that with the fact that the SLR has a motor drive and AF, and it make sense to me to keep it.
Sell the lenses you don't use but keep one or two and the F6. Buy an M6 and be happy.